Oracle® Fusion Middleware C++ API Reference for Oracle Coherence: InKeySetFilter Class Reference

Detailed Description

Filter

filter

Author:

djl 2008.04.14

Public Types

typedef spec::Handle

Handle

InKeySetFilter Handle definition.

typedef spec::View

View

InKeySetFilter View definition.

typedef spec::Holder

Holder

InKeySetFilter Holder definition.

Public Member Functions

virtual bool

evaluateEntry (Map::Entry::View vEntry) const

Apply the test to a Map::Entry.

Parameters:

vEntry

the Map::Entry to evaluate; never NULL

Returns:: true if the test passes, false otherwise

virtual bool

evaluate (Object::View v) const

Apply the test to the object.

Parameters:

the object to test

Returns:: true if the test passes, false otherwise

virtual size32_t

calculateEffectiveness (Map::View vMapIndexes, Set::View vSetKeys) const

Given a Map of available indexes, determine if this IndexAwareFilter can use any of the indexes to assist in its processing, and if so, determine how effective the use of that index would be.

The returned value is an effectiveness estimate of how well this filter can use the specified indexes to filter the specified keys. An operation that requires no more than a single access to the index content (i.e. Equals, NotEquals) has an effectiveness of one. Evaluation of a single entry is assumed to have an effectiveness that depends on the index implementation and is usually measured as a constant number of the single operations. This number is referred to as evaluation cost.

If the effectiveness of a filter evaluates to a number larger than the keySet.size() * <evaluation cost> then a user could avoid using the index and iterate through the keySet calling evaluate rather then applyIndex.

Parameters:

	vMapIndexes	the available MapIndex objects keyed by the related ValueExtractor; read-only
	vSetKeys	the set of keys that will be filtered; read-only

Returns:: an effectiveness estimate of how well this filter can use the specified indexes to filter the specified keys

virtual Filter::View

applyIndex (Map::View vMapIndexes, Set::Handle hSetKeys) const

Filter remaining keys using a Map of available indexes.

The filter is responsible for removing all keys from the passed set of keys that the applicable indexes can prove should be filtered. If the filter does not fully evaluate the remaining keys using just the index information, it must return a filter (which may be an EntryFilter) that can complete the task using an iterating implementation. If, on the other hand, the filter does fully evaluate the remaining keys using just the index information, then it should return NULL to indicate that no further filtering is necessary.

Parameters:

	vMapIndexes	the available MapIndex objects keyed by the related ValueExtractor; read-only
	hSetKeys	the mutable set of keys that remain to be filtered

Returns:: a Filter object (which may be an EntryFilter) that can be used to process the remaining keys, or NULL if no additional filter processing is necessary

virtual void

readExternal (PofReader::Handle hIn)

virtual void

writeExternal (PofWriter::Handle hOut) const

virtual TypedHandle
< const String >

toString () const

Output a human-readable description of this Object to the given stream.

Note that when overriding this method the return type must be TypedHandle<const String> rather then String::View. These two types are assignment compatible but not equivalent and declaring the override with String::View will not be a compatible override.

coherence::lang::operator<<(std::ostream, Object::View) is defined and will call into the toString method, to output Objects. If a managed String object is desired, the COH_TO_STRING macro can be used to build up a String from streamable contents and is generally how toString() will be implemented.

 Object::View vKey   = ...
 Object::View vValue = ...
 std::cout << vKey << " = " << vValue << std::endl;

 String::View vs = COH_TO_STRING(vKey << " = " << vValue);

The COH_TO_STRING macro is also the most common way to implement the toString method. For example:

 virtual TypedHandle<const String> Person::toString() const
     {
     return COH_TO_STRING("Name: " << f_sName << " SSN: " << f_nSSN);
     }

Returns:: a string representation of this object

virtual Filter::View

getFilter () const

Obtain the Filter.

virtual Set::View

getKeys () const

Obtain the underying key set.

virtual void

ensureConverted (Converter::View vConverter) const

Ensure that the underlying keys are converted using the specified converter.

Protected Member Functions

InKeySetFilter ()

Default constructor (necessary for the PortableObject interface).

InKeySetFilter (Filter::View vFilter, Set::View vSetKeys)

Construct an InSetFilter for testing "In" condition.

Constructor & Destructor Documentation

InKeySetFilter	(	Filter::View	vFilter,
		Set::View	vSetKeys
	)			`[protected]`

Construct an InSetFilter for testing "In" condition.

Parameters:

	vFilter	the underlying filter
	vSetKeys	the set of keys to limit the filter evaluation to

Member Function Documentation

virtual Filter::View getFilter ( ) const [virtual]

Obtain the Filter.

Returns:: the Filter

virtual Set::View getKeys ( ) const [virtual]

Obtain the underying key set.

Returns:: the underlying key set

Since:: 12.2.1

virtual void ensureConverted ( Converter::View vConverter ) const [virtual]

Ensure that the underlying keys are converted using the specified converter.

This method must be called prior to index application or evaluation when the keys being evaluated exist in an internal form.

Note: for convenience, this method will be automatically called by the partitioned cache service when this filter appears as the outermost filter in a query.

Parameters:

vConverter

the converter that should be used for key conversions